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Closed-circuit television

lastmod 2026-02-27created 2018-12-3197 edits

Closed-circuit television, commonly called CCTV (Closed Circuit Television), is a method of using video cameras to transmit signals to a limited set of monitors at a specific location. It is commonly used for surveillance cameras.

Categories

Python

System integration (SI)

Software

See #List of CCTV Software.

Manufacturers and products

Comparison of major CCTV VMS solutions

See Network Video Recorder#Comparison of major CCTV VMS solutions for details.

Timing Test

  • Sync Timer - Good for timing tests across multiple devices (typically CCTV)

Camera types

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Dome Camera
A small camera with a round dome cover, mounted on the ceiling and used mainly indoors. Because it is mounted on the ceiling, the wiring is hidden and neat, so it is often used with the interior design and people's aversion to cameras in mind. In particular, it is an all-in-one type with the lens and camera integrated, so you do not buy a lens separately. However, it is not waterproofed, so it is almost impossible to use outdoors, and it is also unsuitable for long-range surveillance, but it is relatively inexpensive.
Box Type Camera
It is called a box camera because its exterior is shaped like a rectangular box. It is the most commonly used camera. Compared with dome cameras, box cameras put functionality first, so they are mainly used where long-range or detailed surveillance is needed, and a lens suited to the purpose must be purchased separately. When mounted outdoors, the camera must be installed inside a camera housing, a camera cover that protects it from water and ice, and a bracket that can support it must be attached to the wall or ceiling. To cover blind spots with a single camera, a PTZ (Pan / Tilt) Driver that can adjust the camera left/right and up/down automatically from a distance can be installed in addition.
Dome Camera (Speed Dome Camera)
An all-in-one camera with built-in Pan and Tilt Driver functions that can adjust the camera up/down and left/right, covered with a round dome-shaped cover.
Pan / Tilt / Zoom Camera
An all-in-one camera that adds a pan-tilt function (up/down/left/right adjustment of the camera) to an integrated zoom camera. It is the optimal camera for monitoring wide areas and minimizing blind spots, but it is expensive because it is multi-functional.
Incandescent bulb socket camera (Bulb Camera)
An innovative product introduced recently. Simply screwing it into an existing incandescent bulb socket lets it perform all CCTV functions, and in particular, a micro memory card of up to 32G can be inserted into the product, so it fully performs its own DVR (Digital Video Recoder; digital video recorder) function. It is an innovative product that not only lets you turn the built-in LED lamp on/off remotely but also lets you check it in real time from a PC or smartphone.

Other classifications

Cameras are also classified under various other names, as follows.

CCD Camera
A camera device in which the light signal entering through the lens is converted into an electrical signal by the CCD (solid-state image sensor), the analog signal is converted into a digital signal, and image signal processing in the DSP outputs a video signal so that monitoring is possible. Generally refers to cameras for cctv.
Color cameras and black-and-white cameras
Camera functions are divided into color and black-and-white, and these days color cameras are used in most cases.
Integrated zoom camera
A zoom lens is attached to a rectangular box camera, so you do not need to buy a separate lens.
Camera Housing
Equipment used to protect the camera from dust and the external environment and to give it a neat appearance; choose one that suits the location and installation position. A temperature control device can also be installed inside, so it can be used even in extreme environments. Housing types include indoor general-purpose (simple dust-proof/waterproof / fully sealed / ventilated), outdoor general-purpose (simple dust-proof/waterproof / fully sealed / ventilated), and special-purpose (forced air-cooled / water-cooled / explosion-proof / special protection / other uses).
Pan/tilt driver (Pan/Tilt Driver: up-down/left-right adjuster)
A rotator that carries the CAMERA and rotates it up-down and left-right. It is equipment for extending the surveillance range and for eliminating areas not captured in the camera image (blind spots).
Made of STEEL and extruded plastic, and classified by payload capacity and whether it is waterproof.
PAN TILT units are classified as small, medium, and large by payload weight. (See pan-tilt in the product introduction section) (Depending on the installation, there are 2 types: fixed pan-tilt and motorized pan-tilt. A fixed pan-tilt can be adjusted about 15~30 degrees horizontally and about 45 degrees vertically and is ultimately fixed in place. A motorized rotator can remotely control the camera's shooting direction up, down, left, and right, and comes in many types.
Omniscan Dome Camera
A dome-shaped device designed and built to blend in with the surrounding interior. It is mainly used in high-end buildings where the interior matters and in important buildings where security matters, and it can perform the camera housing and pan/tilt functions at the same time. The pan/tilt structure and top cover are installed above the ceiling to minimize exposure, and the pan/tilt structure uses DC stepping motors to minimize noise and vibration during rotation. The lower cover directly affects the camera image, so it is made of a high-grade special material with good light transmittance and no refraction.

Screen size (resolution)

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Vertical resolution is generally used. The following all mean the same thing. 

200만화소 = 2M =2MP = 2메가픽셀 = 1080P = FHD = FULL HD

See Resolutions for details.

Average specs required by the industry

2MPixel (FHD)

H264 video size calculation

See H264.

Basic information for intelligent CCTV

May be installed for crime prevention, facility guidance, and fire prevention
Installation prohibited in places where it invades privacy, such as bathrooms, toilets, sauna rooms, and changing rooms
Restrictions on CCTV installation and operation [administrative fine of up to KRW 30 million / 50 million]
Post a CCTV notice sign in an easily visible place
State the installation purpose, the recording location and range, and the contact details of the person in charge
CCTV notice sign installation [administrative fine of up to KRW 10 million]
No audio recording and no arbitrary manipulation
Prohibits arbitrarily manipulating the camera beyond its original installation purpose or pointing it at other places
No audio recording or arbitrary manipulation [up to 3 years of imprisonment or a fine of up to KRW 30 million]
No unauthorized leak or disclosure of CCTV video information
When providing personal video information, provide only the minimum necessary after verifying the person's identity, and apply pixelation to other people in the video
No unauthorized leak or disclosure of CCTV video information [administrative fine of up to KRW 10 million]
Establish and publish a CCTV operation and management policy
Designate an officer responsible for personal video information, and publish the CCTV operation and management policy on the website, etc.
Establishing and publishing a CCTV operation policy [administrative fine of up to KRW 10 million]
Measures to ensure the security of CCTV video information
Control access by anyone other than administrators, issue an individual ID to each administrator, and provide locking devices
Secure management of CCTV video information [administrative fine of up to KRW 30 million; in case of a leak due to non-compliance, up to 2 years or a fine of up to KRW 10 million ]

Installation methods/types

PoE+IP-CCTV+NVR(HVR)
Digital; built on top of an internet network.
Coaxial cable (BNC cable)+DVR
Analog; due to the characteristics of coaxial cable, the transmitted video is distorted

How to choose CCTV

Outdoor surveillance

When you install a camera for outdoor surveillance, it is affected by all kinds of external conditions. Dust, rain, wind, people with hammers, and so on: a camera for outdoor use must be ready to cope with these external conditions.

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A vandal camera is a camera whose exterior is made of high-strength material so it can withstand external impact. Outdoors, use a Vandal camera so that external impacts do not affect the camera.

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An IP66 rating means the camera is completely protected from dust and protected from high-pressure water jets from any direction. A camera installed outdoors and exposed to rain and wind must have a valid IP66 rating.

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A housing connects a mount to the camera and helps you easily install it at the desired position. It also protects the camera from external impact, sunlight, heat, etc., so when installing a camera outdoors, it is good to install a camera with an integrated housing.

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The Defog function is a technology that corrects video blurred by fog to make it clear. If you have to install a camera where fog or smoke may block its view, a camera with the Defog function is recommended.

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When a camera is installed at a high outdoor place such as on top of a utility pole, or where vibration can occur, the camera may shake due to strong wind or external vibration. When the camera shakes, the DIS function shows the shaky video clearly through image correction.

Surveillance at night

At night there is less light than during the day, so even when the camera records video, it is hard to see. When using a surveillance camera in such low-light conditions, you must consider lighting, video brightness, and noise control. Therefore, night surveillance needs the following functions

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The Day&Night function applies settings suited to bright conditions and dark conditions respectively, depending on the amount of light in the installation environment. Day&Night functions include the ICR method, which corrects using a filter, and the software (Electrical) method, which corrects in software.

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An IR camera is a camera that includes infrared LEDs. Because an IR (infrared) camera shows the image reflected from its IR LEDs, it can clearly capture objects even with almost no light. Suitable for spaces with almost no lighting at night

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When shooting in a dark environment, forcibly correcting the video to brighten a dark screen produces noise in the video. The SSNR function removes noise from the video. For cameras used in dark places, choosing a camera with the SSNR function is better for capturing clearer video.

Not missing small details

Places such as bank or store counters and ATMs need overall surveillance, but the camera must also be able to accurately capture and detect relatively small things such as people's faces or the type of currency

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A megapixel camera uses more pixels than other low-resolution cameras to represent the same area. As a result, it represents fine details more accurately and in more detail, and keeps higher image quality than low-resolution cameras even when part of the image is enlarged. So if the camera's purpose is to focus on details, a megapixel camera is suitable.

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If you want to close in on a small changing part of the whole screen, it is good to use a camera with an optical zoom function. With optical zoom, you can enlarge part of the screen without any change in image quality.

Monitoring suspicious moving objects

When monitoring a space, special functions are needed to properly monitor unusual, potentially suspicious movement when it occurs. Using cameras or functions specialized in monitoring moving objects, such as the following, lets you build a more efficient surveillance environment.

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A PTZ camera is a camera that can adjust its lens direction and magnification. During surveillance, it can zoom in on potentially suspicious objects or turn the camera to follow movement.

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The Tracking function tracks moving objects. A camera with the Tracking function tracks the subject based on preset values.

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The video analytics and motion detection functions detect movement in the video as events according to their respective settings. Video analytics includes passing detection, entering/exiting detection, and appearing/disappearing detection.

Surveillance where the light position changes

Cameras are generally installed with the direction of light in mind. However, when backlighting occurs because sunlight faces the camera as the sun moves, smooth surveillance becomes difficult. If a location is optimal for surveillance but backlighting occurs there, it is good to install a camera that includes the following functions.

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When lighting faces the camera and backlighting occurs, the WDR function is needed. When capturing the scene, the WDR function shoots the same scene once so that bright areas are clearly visible and once more so that dark areas are clearly visible, then combines them so that both are clearly visible.

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When part of the video is dark due to backlighting, such as building shadows, using the SSDR function makes the system detect the dark areas, keep the bright parts of the video, and boost the signal of the dark parts so that they are clearly visible.

CCTV configuration

Exposure

Exposure refers to the amount of light entering the image sensor through the camera lens.

High exposure means a large amount of light enters the image sensor through the lens. Because there is more light, the higher the exposure, the brighter the video is overall. Low exposure means a small amount of light enters the image sensor through the lens. Because little light enters the image sensor, video with low exposure is darker than video with high exposure. Therefore, the user must adjust the exposure appropriately for the environment. For example, in a dark environment, set the exposure high so the scene is captured brightly, and in a bright environment, lower the exposure so that too much light does not enter and saturate the screen.

Cctv-setting-exposure.png

(Left) Video with high exposure vs (Right) Video with low exposure

Notes:

  • If the background is darker than the subject, lower the exposure so the subject looks normal.
  • Conversely, if the background is brighter than the subject, increase the exposure so the subject looks normal.

Brightness

Adjusts the screen brightness. The higher the number, the brighter the screen.

Minimum shutter

The shutter can set the sensor exposure automatically according to the environment, and the electronic shutter operates within the range from minimum shutter to maximum shutter. Minimum shutter is the minimum value of the possible slow exposure time range and sets the limit for long exposure times.

If the selected minimum shutter value is smaller than the fps value of the [Sensor] mode, the frame rate may drop in dark conditions.

Maximum shutter

Maximum shutter is the maximum value of the possible fast exposure time range and sets the limit for short exposure times.

User preferred shutter

Sets the appropriate exposure time that takes priority within the exposure time range.

Anti-flicker

Prevents screen flickering caused by a frequency mismatch with the lighting in the shooting environment.

SSNR

Removes noise from the video. (Supported options may vary by camera specifications.)

  • On/Off: Sets whether to use the SSNR function. Selecting [On] lets you adjust the SSNR level.
  • Intelligent NR: When there are moving objects in the video, automatically adjusts the noise reduction level to improve object identification.
  • Intelligent NR Ⅱ: When people or vehicles move in the video, automatically adjusts the noise reduction level to reduce smearing of moving objects and improve identification.

SSNR 2D level

SSNR 2D reduces video noise using adjacent pixels within one frame. Sets the SSNR 2D level value. Can be set when [SSNR] is set to [On] or [Intelligent NR].

The higher the level, the more noise is reduced, but the video may become blurry.

SSNR 3D level

SSNR 3D reduces video noise using pixels from multiple frames. Sets the SSNR 3D level value. Can be set when [SSNR] is set to [On] or [Intelligent NR].

The higher the level, the more noise is reduced, but video smearing may occur.

Iris

Selects the iris type. (Supported options may vary by camera specifications.)

  • DC (Auto): Adjusts the iris automatically according to the amount of ambient light.
  • Manual: Adjusts the iris F-number manually.
  • P-Iris: Adjusts the iris with a stepping motor. It can bring multiple objects at various distances into focus at the same time, giving a deep depth of field.

Iris F-number

Enabled when the [Iris] mode is [Manual]; sets the iris F-number.

AGC

AGC (Auto Gain Control) adjusts brightness by adjusting the sensitivity of the video gain when shooting a subject in dim lighting.

  • Off: Does not use the AGC function, which amplifies the gain of the video signal so a dark screen can be seen brightly. If you select this option, the [SSNR] and [Day/Night mode] functions do not work.
  • Manual: Adjusts the AGC value manually.
  • Max gain: Sets the maximum gain up to which the gain can be controlled automatically according to ambient brightness.

Level (manual)

Sets the AGC level value manually as desired. The higher the level value, the higher the gain, so the screen becomes bright even in dark environments.

Level (max gain)

Sets the max gain value. The gain is controlled automatically up to the set max gain according to ambient brightness. The higher the level value, the higher the max gain.

Other notes

    • Depending on the minimum and maximum shutter range settings, the screen may become saturated by exposure.
    • After setting Intelligent NR mode (SSNR 2D and SSNR 3D), it may take some time for the effect to be applied/released.
    • When Intelligent NR mode (SSNR 2D and SSNR 3D) is applied, video identification improves, but noise may increase.
    • In bright environments with little noise, Intelligent NR (SSNR 2D and SSNR 3D) may not have much effect.
    • When Intelligent NR (SSNR 2D and SSNR 3D) is set, motion detection in the video uses the motion detection function internally, so it follows the operating conditions of motion detection events. Detailed motion detection settings can be found in [Analytics] > [Motion detection].
    • When AGC usage is high, the SSNR 3D value of SSNR increases, so smearing may occur in the video.
    • Screen noise increases when AGC operates.
    • If the AGC mode option is set to [Off] or [Manual], or the [Max gain] value is set below 30 db, the [Auto] option of [Day/Night mode] cannot be set.

Depth of field and aperture

When the aperture size is changed to adjust exposure, not only the brightness changes but also the range that is in focus, depending on the aperture size; this in-focus range is called depth of field. A shallow depth of field means the in-focus range in the whole frame is small, and a deep depth of field means the in-focus range in the whole frame is wide. A small F-number makes the depth of field shallow, and a large F-number makes it deep. Therefore, if you open the aperture wide to brighten the video, the F-number becomes small, so the in-focus range in the whole frame may become small.

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(Left) Example of shallow depth of field vs (Right) Example of deep depth of field

Shutter speed

Shutter speed is the time during which the image sensor receives light while capturing one frame. With a short shutter speed, light is received only for a short time, so the screen becomes darker. However, momentary movement can be captured cleanly in the video. With a long shutter speed, the image sensor receives light for a long time. Because there is more light, you get a bright screen. However, fast-moving subjects look as if their movement is dragged or leaves afterimages.

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(Left) Short shutter speed vs (Right) Long shutter speed

Shutter speed is expressed in the form 1/n. If the shutter speed is '1/250', light is collected for 1/250 second to compose one frame

Gain

When the video does not get brighter even with exposure adjustment, adjust the gain to control the video brightness. Adjusting the gain controls the strength of the camera video's electrical signal; it adjusts brightness by amplifying the video's electrical signal. Raising the gain increases the signal strength: the higher the gain value, the more the signal is amplified and the brighter the image. However, raising the gain also increases image noise, so the higher the gain value, the more even small noise is amplified to look large, and the video is no longer clean.

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(Left) Before gain adjustment vs (Right) Image with increased gain

Backlight

Backlighting is a phenomenon where the object is located between the camera and the light source, so the background is captured very brightly but the object is captured very darkly. When backlighting occurs, shooting based on the bright background makes the object dark and hard to distinguish, and shooting based on the dark object makes the background too bright, making surveillance difficult.

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(Left) Video shot based on the bright background vs (Right) Video shot based on the dark object

User backlight compensation (BLC)

BLC (Back Light Compensation) mode lets the user set a specific area in video that is captured dark due to backlighting, and corrects it so that objects in the selected area are more visible.

HLC (Highlight Compensation Capability)

Use the HLC function when strong light such as streetlights or car headlights faces the camera and interferes with smooth surveillance. The HLC function effectively blocks strong lighting such as headlights; it masks a specific area chosen by the user to prevent glaring light from hindering recognition of license plates or subjects. The HLC level adjusts the brightness level at which highlight areas are masked, and the mask tone menu adjusts the brightness of the masking color.

  • Mask color - Sets the color of the blocked area.
  • Mask tone - Sets the tone of the blocked area.
  • Dimming - Detects areas of strong light on the screen and adjusts brightness to reduce saturated areas.

Notes:

  • At night, it operates only when highlights larger than a certain area enter in a dark environment.
  • At night, HLC does not operate in conditions that are bright overall or too dark. In the daytime, HLC does not operate in conditions that are too dark.
  • When HLC is set, the HLC area has a minimum and maximum size to prevent malfunction.
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The screen output in ddrm when applying camera settings -> HLC. Edges somehow seem to come out bright.

WDR (Wide Dynamic Range)

WDR (Wide Dynamic Range) mode makes both dark and bright areas clearly visible in a backlit environment. Using the camera's dual shutter, it shoots once with a short shutter so bright areas are clearly visible and once more with a long shutter so dark areas are clearly visible, then combines only the clearly visible parts of the two images into one. When WDR mode is used, noise may occur between bright and dark areas.

Cctv-setting-wdr.png

(Left) Video before the WDR function is applied vs (Right) Video with the WDR function applied

Because the WDR function makes one frame from two frames, on some models the video may look choppier than when the WDR function is not used.

Notes:

  • Selecting WDR mode resets the shutter value. As a result, the screen brightens and then darkens.
  • When WDR mode is used, the frame rate is halved.
  • WDR mode is recommended when the camera is installed indoors and there is strong backlight.
  • In WDR mode, noise may occur between bright and dark areas.
  • In WDR mode, noise may occur in areas with motion.
  • In WDR mode, the following may occur depending on lighting conditions, so turn WDR mode off.
    • When colors change unnaturally or the screen looks unnatural
    • When noise appears in bright areas of the screen
  • WDR performance may vary with the size of the bright areas on the screen, so adjust the installation angle for optimal WDR performance.
  • Setting the WDR level high may make the screen look unnatural.
  • For optimal WDR performance, it is recommended to set the iris of exposure compensation to [Auto].

Noise

Environments where noise occurs: when shooting in a dark environment, if the gain is forcibly set high to brighten a dark screen, noise occurs in the video.

  • Ways to remove noise from video
  • 2D DNR (Digital Noise Reduction)

2D DNR corrects a noisy pixel by referring to the pixels around it. It is effective at removing noise from moving objects, but when removing noise from fixed objects such as the background, it has the drawback of lowering resolution, for example through blurring.

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White Balance

You can correct the image so that white comes out exactly white under any lighting, and other colors look normal based on white.

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(Left) Video A with incorrect white balance vs (Right) Video B with incorrect white balance

Adjusting the white balance means adjusting the camera's color balance in advance so that the camera reproduces colors accurately. The human eye perceives white paper under sunlight and white paper under fluorescent light as the same white. If you actually observe the colors, white paper under sunlight is orange-tinted and white paper under fluorescent light is blue-tinted, but the human brain logically corrects this difference and perceives both as white. A camera, however, has nothing like the human brain, so the same scene appears differently depending on the color of the lighting. In other words, the colors in the video can be distorted depending on external lighting or light conditions, so white balance is adjusted to represent colors accurately.

Adjust the white balance by choosing the setting below that best suits the current surveillance situation.

  • ATW : Corrects the camera's colors automatically.
  • AWC : Uses an object such as white paper to correct colors so they are optimized for the current light source and screen. Point the camera at a white object and press the AWC Set button, and the colors are corrected automatically based on that object.
  • Manual : Corrects colors by adjusting Red Gain and Blue Gain directly.
    • If there is too much red, lower the red gain,
    • if there is too much blue, lower the blue gain.
    • If there is too much green, raise both the blue and red values.
  • Outdoor : Corrects colors automatically to suit outdoor lighting such as sunlight.
  • Indoor : Corrects colors automatically to suit indoor lighting.
  • NarrowATW : Corrects the camera's colors automatically in 2800 K ~ 9000 K environments. The color temperature range is narrower than in [ATW] mode.
  • MERCURY : Corrects the camera's colors automatically to be optimized for mercury lamp lighting.
  • SODIUM : Corrects the camera's colors automatically to be optimized for sodium lamp lighting.
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Video with corrected white balance

White balance may not work properly in the following cases. In that case, adjust the white balance with [AWC] mode.

  • When the surroundings of the subject are outside the color temperature correction range, such as a clear sky or sunset
  • When the surroundings of the subject are dark
  • When the camera points directly at a fluorescent light or the lighting changes a lot

BNC-terminal CCTV installation guide

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RCA-terminal CCTV installation guide

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Using network bandwidth effectively

When the size of data sent by cameras grows, more hard disks are needed to store it, and the viewer (CMS) that displays the screen also needs more resources to process the large amount of data. It also affects the network that makes up the network system. To solve these problems, you can expand the network, increase storage, and use high-spec systems to process the data, but these alternatives add cost and make the system expensive to build. For this reason, how to optimize data size while keeping the monitored video clear has become an issue. This explains how to build and operate an effective network surveillance system by getting optimal video from network cameras with minimal data.

  • Codec choice: MJPEG (motion jpeg), H.264, H.265, etc.
  • GOV length
  • Bitrate control: VBR (Vaiable bitrate, variable bitrate) or CBR (constant bitrate, constant bitrate)
    • Use CBR to run a stable system: 2
    • and it is good to use VBR to run an efficient system: 3
  • Setting the optimal resolution/FPS
  • Multicast or unicast

Terminology

Varifocal lens (VARIFOCAL LENS)
A lens whose focal length can be varied.
It varies the focal length continuously by moving an auxiliary lens in front of the main lens, but unlike a zoom lens, the image plane also changes.
Visible light (VISIBLE LIGHT)
Light that the human eye can see
Electromagnetic waves with wavelengths in the range of about 380nm∼780nm.
Sensitivity (SENSITIVITY)
A term for the degree to which various devices or sensors respond to input
① The minimum input level needed to produce the desired output
For TV and VIDEO CAMERAs, defined as the received input level or subject illuminance needed to obtain the desired S/N ratio
② The magnitude of output per unit input. For optical sensors etc., photoelectric sensitivity, defined as output current per incident luminous flux, is generally used
Gamma (GAMMA)
For the input-output relationship of light-to-electricity conversion devices such as image pickup and display devices, or of image-to-image conversion devices, with output on the vertical axis
and input on the horizontal axis, it is the slope representing the input-output conversion characteristic
This is generally the conversion characteristic (called the photoelectric conversion characteristic for image pickup devices and the electro-optical conversion characteristic for display devices
If gamma is 1, input and output are proportional; if gamma is greater than 1, contrast becomes stronger,
and if gamma is less than 1, conversely, a screen with weaker contrast is output
Gamma compensation (GAMMA COMPENSATION)
Most image pickup devices (pickup tubes, CCD, MOS, etc.) have a linear (γ=10) photoelectric conversion characteristic for incident light, but the representative image display
means, the cathode-ray tube (CRT), has a nonlinear (γ=22) electro-optical conversion characteristic, so image distortion occurs due to the mismatch in conversion characteristics
Therefore, an inverse nonlinear (γ=045) correction to cancel the CRT's nonlinear (γ=22) characteristic is performed on the camera side
so that, as a result, the CRT's luminous sensitivity is proportional to the incident light
Ghost (GHOST)
An interfering image that appears when receiving TV signals, offset from and overlapping the regular signal
Mainly occurs because waves reflected from buildings or terrain arrive with a time difference and are received in duplicate
Another cause is unstable FIELD matching between the receiving antenna and the receiver, which produces reflections
Fixed focal length lens (FIXED FOCAL LENGTH LENS)
A lens whose focal length cannot be changed
Besides standard lenses, there are various types such as telephoto and wide-angle lenses
Generally offers better imaging precision than zoom lenses with variable focal length
Solid-state image sensor (SOLID STATE IMAGE SENSOR)
An image pickup device whose video signal is read out by a semiconductor scanning circuit
The light-receiving part consists of many pixels that generate and accumulate signal charge from incident light
The signal charge accumulated in each pixel is read out in a prescribed order through switching transistors
Smaller, lighter, more durable, and easier to operate than vacuum-type image pickup devices such as pickup tubes
There are LINEAR sensors with pixels arranged in one dimension and two-dimensional AREA sensors; starting with broadcast cameras and
home video cameras, they are used in many fields such as office equipment, medical, and business use
Using a low-noise CCD as the scanning circuit is the mainstream
Optical filter (OPTICAL LOW PASS FILTER)
An optical LOW PASS FILTER for removing unnecessary spatial frequency components contained in an image
Often uses the multiple images produced by the birefringence of quartz crystal
Needed in cameras using solid-state image sensors to prevent reflection noise caused by discrete sampling of the image
Aperture ratio (APERTURE RATIO)
The ratio (D:f) of the diameter (D) of the entrance lens of an optical system to its focal length (f)
That is, with a focal length of 50mm and an entrance lens diameter of 25mm, it is written 1:2
This indicates the brightness of the optical system; the F-number of a lens is the reciprocal of the aperture ratio, written F=f/D
Noise (NOISE)
Electrical energy or interference that produces white spots or black dots on the screen
Network camera (NETWORK CAMERA)
A camera based on a high-performance embedded system with a built-in CCD camera that digitizes and compresses video and can send the data over a network, so the video can be restored and viewed in real time from anywhere in the world over the internet. Because it is a web-based digital camera system, it needs no separate video cable or control equipment, only an existing network cable and internet line.
Dynamic range (DYNAMIC RANGE)
The ratio between the maximum level at which a signal can be transmitted, converted, or processed without distortion and the minimum level limited by noise and device characteristics. In imaging systems,
the maximum level is limited by saturation of circuits and conversion devices, blooming, etc., and the minimum level by noise, SHADING, the number of quantization levels, etc.
The unit is usually dB
Dichroic prism (DICHROIC PRISM)
A prism with a multilayer interference film formed on its surface that reflects only some wavelength components of incident light and transmits the remaining components,
separating the light into the R, G, B primary colors
Because there is almost no loss of transmitted light, it is used in the color separation systems of multi-chip VIDEO CAMERAs and LCD projectors
Single-chip color camera (SINGLE CHIP COLOR CAMERA)
A color camera that captures color with a single solid-state image sensor
Various types of color filters are arranged in a mosaic or
stripe pattern over each element of the image sensor to obtain color information from a single image sensor
There are the primary-color single-chip method, which uses the RGB primary colors for the color filters, and the complementary-color single-chip method, which mainly uses
complementary colors; the complementary-color single-chip method, which is superior in resolution and sensitivity, is mainly used
Decibel (DECIBEL, dB)
When the reference power difference is P1 and the compared power difference is P2, it is the unit of the value N representing the relative comparison defined by the following formula
NP = 10 * LOG10(P2/P1)
The common logarithm of the power ratio is the BELL, and 10 times that is expressed as the DECIBEL (dB)
The voltage ratio (E2/E1) and current ratio (I2/I1) are expressed by the formulas below
NE = 20 * LOG10(E2/E1), NI = 20 * LOG10(I2/I1)
Generally aligns the frequency and phase of sync signals
Digital recording (DIGITAL RECORDING)
Technology that stores images captured by a camera on a computer's hard drive.
A digital video recorder (DVR) has many advantages over a typical tape recorder (VCR), such as clearer images, faster search, and long-term recording.
Digital zoom
Zoom is broadly divided into Optical Zoom and Digital Zoom.
Optical Zoom uses the lens, and Digital Zoom refers to enlarging the screen using digital image processing technology.
Generator lock (GENERATOR LOCK, GEN-LOCK)
Fully synchronizing the sync signals between systems that use two or more different sync signals
Sync signal (SYNC SIGNAL)
A signal used in an image transmission system to match the reproduction on the receiving side with the transmitting side
TV must be synchronized horizontally and vertically, and for this, a composite sync signal combining the horizontal sync signal and
the vertical sync signal is inserted during the blanking interval of the video signal
It is normally sent with (-) polarity, which allows amplitude separation, but (+) polarity is also used in satellite transmission
Coaxial cable (COAXIAL CABLE)
A type of cable with low loss in its pass band. This cable consists of a metal shield and, at its center,
one or more conductors, and the shield and conductors are separated from each other
Dynamic resolution (DYNAMIC RESOLUTION)
Resolution for a moving subject
Ordinary image sensors use the accumulation principle, so they integrate the signal from incident light over a certain time before reading it out
If the subject moves beyond the resolving power of a still image during this readout cycle, the dynamic resolution becomes worse than the still image resolution
Therefore, the shorter the accumulation time, the better the dynamic resolution, but the sensitivity worsens accordingly
Display (DISPLAY)
The task of visually displaying data, and the display device.
Lux (LUX)
A unit for measuring the sensitivity of light
Moiré (MOIRE)
An image distortion phenomenon that occurs in video cameras when capturing a subject that contains frequency components interfering with the quantization frequency, which depends on the TV system standard and the pixel count of the image sensor used. When a particular subject (regular vertical stripes, radiating patterns, checkered patterns) is captured at a particular size, irregular colors that look like heat haze appear overlaid.
This image distortion can be reduced by adopting an appropriate optical LPF matched to the pixel count of the image sensor.
Back focal distance (BACK FOCAL DISTANCE): the distance from the vertex of the lens's last refracting surface to the image focal plane.
Motion detection (MOTION DETECTION)
A function that automatically detects moving objects. There are methods that use sensors and methods that observe whether the image has changed and judge that there was motion if the screen information has changed from before. To improve the function, the screen is generally divided into blocks, image changes are judged block by block, and the size of the change threshold per block and the number of blocks for judging motion can be set
Back focal distance (BACK FOCAL DISTANCE)
The distance from the vertex of the lens's last refracting surface to the image focal plane
Composite video signal (COMPOSITE VIDEO SIGNAL)
A color signal in which the luminance signal and two color-difference signals are multiplexed by frequency INTERLEAVE
Also called the VBS (VIDEO/BURST/SYNC) signal
Blooming (BLOOMING)
A phenomenon on the video screen where the area around high-luminance parts of the subject becomes bright as if smeared
In solid-state image sensors, blooming occurs because the signal charge accumulated during the accumulation period flows into the surrounding pixels
For this reason, an OVER FLOW DRAIN structure is used to discharge excessively accumulated charge to the substrate
Backlight (BACK LIGHT)
A situation where strong light is projected from behind the object, so the object's brightness looks relatively low.
Video-type auto iris lens (VIDEO TYPE AUTO IRIS LENS)
A type of auto iris lens that receives DC power and a video signal and has a circuit in the lens itself that keeps the amount of light constant;
a lens that judges the level of the video signal and can adjust the lens iris automatically
Interlace scanning (INTERLACE SCANNING)
In TV scanning, to eliminate the flickering the human eye perceives on the screen, every other line is scanned,
a scanning method that completes one picture with 2 horizontal scanning passes
This interlace scanning is currently widely adopted as the standard method in countries around the world
Chromatic aberration (CHROMATIC ABERRATION)
Aberrations in image position, magnification, etc., that occur because the refractive index of optical components such as lenses differs with the wavelength of light
The shift in image position on the optical axis due to color is called axial chromatic aberration, and the shift in magnification is called lateral chromatic aberration
In electron optics, the aberration caused by the energy spread of electron beams is also sometimes called chromatic aberration
Color signal (COLOR SIGNAL)
A general term for signals carrying color information in color TV. R/G/B primary color signals, R-Y/B-Y color-difference signals, carrier chrominance signals, etc., are distinguished by use depending on the case
Color temperature (COLOR TEMPERATURE)
Also called Kelvin temperature, and denoted by the symbol K
When an ideal black body is heated, it goes from dark red to orange, yellow, and white-hot, and the higher the temperature, the bluer the light it emits
That is, it comes from the research of Kelvin of Britain, which showed that the hue of light can be expressed in units of absolute temperature; K is his initial
Midday sunlight is 5,500∼6,000K; as the color temperature goes down, red becomes stronger, and as it goes up, blue becomes stronger
Manual iris lens (MANUAL-IRIS LENS)
A lens used with the IRIS set to a fixed position. Generally used at a fixed brightness,
and a separate correction circuit such as an electronic SHUTTER IRIS is needed to obtain a constant output level
Vertical scanning (VERTICAL SCANNING)
Scanning in the up-down direction
Sequentially reading out the signal values of the pixels making up the screen in the up-down direction, i.e., perpendicular to the horizontal scanning lines,
or sequentially recording or displaying them in the same way
Vertical resolution (VERTICAL RESOLUTION)
Spatial resolution in the vertical direction
Closely related to the pixel count for image sensors, the beam size for pickup tubes, and the broadcast system
The unit is lines (LINE)
Horizontal scanning (HORIZONTAL SCANNING)
Scanning in the horizontal direction
Sequentially reading out the signal values of the pixels making up the screen in the horizontal direction, or sequentially recording or displaying them in the same way
Horizontal resolution (HORIZONTAL RESOLUTION)
Spatial resolution in the horizontal direction
In TV, expressed as the number of black and white vertical lines that can be distinguished on the screen
The unit is lines (LINE)
Progressive scanning (PROGRESSIVE SCANNING)
A type of image scanning method that scans all scanning lines in order within one frame period
It is the simplest scanning method, but from the standpoint of bandwidth compression of the image signal, current TV adopts interlace scanning
However, because of problems inherent to interlace scanning, progressive scanning has recently been re-evaluated,
and receivers that convert received interlaced signals to progressive scanning for display have also been put into practical use
Signal-to-noise ratio, S/N ratio (SIGNAL TO NOISE RATIO, S/N RATO)
The ratio of signal to noise
Usually expressed as the power ratio of signal and noise, but sometimes as a voltage ratio
Switcher (SWITCHER)
Equipment that lets video captured by several cameras be shown on one or several monitors, either in sequence or as a specific screen only.
Backlight compensation (BACK LIGHT COMPENSATION)
When there is strong light around the subject to be observed in the whole frame and an auto iris lens or the like is used,
the iris is controlled by the overall screen level, so the subject to be observed is captured dark; this is a circuit-based correction method for seeing that subject brightly
Mainly, a method is used that divides the screen so that the area to be observed can be selected, and controls the iris based only on the selected area
Aperture compensation (APERTURE COMPENSATION)
Emphasizes the contours of the monitor image to obtain a sharp image
Contour compensation is mostly horizontal, but with advances in digital technology, many video cameras emphasize contours in both the horizontal and vertical directions
Excessive emphasis makes a strong white line appear behind black contours, degrading image quality
Effective pixel count
All the pixels formed on a CCD chip are called the total pixel count; in contrast, the effective pixel count is the number of pixels actually involved in forming the image.
The periphery of the CCD contains output sections that send signals, etc., so this part (about 10%) is not involved in forming the image. A 410,000-pixel CCD typically has 380,000 effective pixels, and a 270,000-pixel CCD has 250,000 effective pixels.
Auto iris lens (AUTO IRIS LENS)
A type of auto iris lens that receives DC power and a video signal, has a circuit in the lens itself that keeps the amount of light constant, and judges the level of the video signal to adjust the lens iris automatically.
Embedded (EMBEDDED)
Refers to a control system in which a processor is built into the system and operates there. It usually refers to any system with a microprocessor regardless of the microprocessor's size or performance, but the scope is generally limited to systems using microprocessors of 32 bits or less. Embedded systems usually impose many restrictions on the system to lower the overall system price and power consumption.
They are also often used when you want to run a specialized real-time operating system rather than a general-purpose operating system.
Web video server (VIDEO SERVER)
A server that stores color moving images and audio so that this data can be used from terminals connected through communication lines and local area networks (LAN).
Intranet (INTRANET)
With the arrival of the internet, the intranet emerged as a new concept replacing groupware in existing office environments. A network within an office that uses the same TCP/IP protocol as the internet is called an intranet.
With groupware, installing the program for each user was a hassle and upgrades cost a lot of money and time, but an intranet overcomes these drawbacks, and an intranet is used through a web browser. One of its big advantages is that it can connect naturally to the internet.
Intranets are expanding their market further thanks to the popularization of the internet, improved web browser features, and more applications based on TCP/IP.
As intranets gained attention, intranet applications have been released here and there, but there is not much software that can be called a dedicated application. Instead, the situation is that a few companies add new features to their existing internet or groupware products.
Internet (INTERNET)
Simply put, the internet is a network of networks made by combining many communication networks.
Through the huge communication network called the internet, you can connect to a distant computer and use it as if it were your own, download various important public files on the internet, search for information, and talk with people in other countries.
You can also exchange opinions with people everywhere and send and receive email. Because the internet uses a special protocol (TCP/IP) to connect various different computers in different locations, communication is possible even if the place you are connecting to on the internet uses a different type of computer.
Automatic gain control (AUTOMATIC GAIN CONTROL, AGC)
A function that controls gain automatically to always keep the output constant in transmission and reception. The output level is fed back to the intermediate amplifier
to control the output level so that it does not fluctuate due to changes in the received signal level, temperature, etc.
Automatic iris control (AUTOMATIC IRIS CONTROL)
A function that adjusts the iris automatically to obtain proper exposure as the shooting illuminance changes
An evaluation value using the average and peak values of the luminance signal is compared with the initial setting, and the difference voltage is used as the iris
control voltage, applying feedback control to keep the signal at a constant level against illuminance changes
Where high precision is required for various subject lighting conditions such as backlight, some use a microcontroller, etc.
Automatic focus (AUTOMATIC FOCUS)
A method of adjusting lens focus automatically; there are the following types.
  • Ultrasonic AF : Emits ultrasound and measures distance from the delay of the reflected wave
  • Infrared AF : Measures distance with infrared light using the principle of triangulation
  • Phase-detection AF : Uses a Hall sensor
  • Contrast AF : Uses the camera's video signal to find the point where a specific frequency component is at its maximum
Electronic shutter (ELECTRONIC SHUTTER)
A shutter operation that changes the signal accumulation time by electronic switching in the image sensor
In solid-state image sensors, a method that discards a certain portion of the total accumulation period and uses only the charge accumulated during the remaining period
is used for shooting fast-moving subjects, preventing fluorescent light flicker, etc.
Illuminance (ILLUMINANCE)
The incident luminous flux converted per unit area; the unit is lux (LUX, LX).
A camera cannot shoot without light, and the number expressing how much light it needs to shoot is called sensitivity; the smaller the value, the better the sensitivity. For surveillance, LUX is usually measured based on IRE (20/30/40), which can be distinguished by eye, and expressed as the corresponding value.
  • Direct sunlight : 100,000 LUX
  • Clear sky : 10,000 LUX
  • Cloudy midday : 1,000 LUX
  • Typical office : 1,000 LUX
  • Audiovisual room : 200 LUX
  • Dusk, hotel lobby : 100 LUX
  • Hotel corridor : 50 LUX
  • Parking lot, theater seats during intermission : 10 LUX
  • Theater seats : 2 LUX
  • Ground on a clear night with a full moon : 0.3 LUX
  • Brightness of a first-quarter moon : 0.001 LUX
  • Brightness of stars : 0.001 LUX
Aspect ratio (ASPECT RATIO)
The ratio of screen width to height in a standard TV system. NTSC and PAL have a horizontal-to-vertical ratio of 4:3, and WIDE systems 16:9
Scanning (SCANNING)
To transmit a two-dimensional image as a temporal electrical signal, the operation of decomposing the image into pixels and
reading out the signal value of each pixel in a fixed order and way
or the operation of restoring the original image from such a signal
Number of scanning lines (NUMBER OF SCANNING LINES)
The number of scanning lines representing one frame, including the vertical blanking interval
525 lines for NTSC, 625 lines for PAL and SECOM, 1125 lines for Hi-Vision, etc.
(There are exceptions, however.) Excluding the vertical blanking interval, it is called the number of effective scanning lines
Scanning standard (SCANNING STANDARD)
The scanning scheme defined for composing an image
The main schemes are line scanning, SECTOR scanning, and point scanning
Zoom lens (ZOOM LENS)
A lens that can change its focal length continuously without changing the position of the subject's image, by moving part of the optical system along the optical axis
A zoom lens for video cameras generally consists of a variator lens group that changes magnification and an imaging lens group that forms the image
Focusing on the image is done by moving some lenses in the variator lens group or the imaging lens group
Generally, the aperture ratio of a zoom lens does not change with the zoom ratio, but to make zoom lenses smaller, some have a larger aperture ratio at the maximum focal length
Zoom ratio (ZOOM RATIO)
The ratio of the maximum focal length to the minimum focal length in a zoom lens or varifocal lens; a value indicating how much the shooting angle of view can be changed
Condenser lens (CONDENSER LENS)
A lens that is not meant to form an image but only to gather light
Used for condensing light in equipment with a light source, such as projectors and slide projectors
Imaging Range
One of the important points in choosing a lens in a CCTV system is deciding at what distance and within what range from the camera position the subject will be shot (captured). This is called the imaging range of the lens. The imaging range is usually determined by the focal length of the lens and the size of the image sensor of the camera used.
Focal length
The distance between the focal point and the principal point of an optical system. In imaging devices, the longer the focal length, the narrower the angle of view and the shallower the depth of field.
Minimum object distance (MINIMUM OBJECT DISTANCE, MOD)
The minimum close distance at which a lens can focus on a subject
Measured as the distance from the front of the lens (VERTEX) to the subject
Generally, wide-angle lenses have a smaller MOD than telephoto lenses
Minimum object illumination (MINIMUM OBJECT ILLUMINATION)
The lowest subject brightness at which an image sensor, or a camera using one, can shoot
Below this brightness, the S/N ratio worsens and a usable video image cannot be obtained
There is no clear standard for the minimum S/N ratio
Color burst (COLOR BURST)
A color subcarrier component of 8∼9 cycles added at a specific position in the BACK PORCH of the horizontal blanking interval of a color TV signal
Used as the reference for hue and saturation when demodulating the color signal from a composite color signal
Cross-color (CROSS-COLOR)
A phenomenon in color TV systems where color signal components mixed into the luminance signal cause problems in image reproduction. Also called cross-color noise
Crosstalk (CROSSTALK)
A phenomenon in communication lines such as telephone lines where part of the power of another line leaks in, mixing in content different from the original communication
Closed-circuit TV (CLOSED CIRCUIT TELEVISION, CCTV)
A TV system intended to serve only specific receivers. The transmitting side and receiving side are connected by wire or a special wireless transmission path so that others cannot easily connect
Used for industrial, educational, medical, and local information services, etc.
Frame (FRAME)
A single picture in TV or film
In NTSC, one frame consists of 525 scanning lines, and there are 30 frames per second
Flange back (FLANGE BACK)
The distance from the reference plane where the lens joins the camera, i.e., the FLANGE, to the focal plane
Also called the flange focal distance (FLANGE FOCAL DISTANCE)
For C-mount lenses, the flange back distance is 17526mm, and for CS-mount it is 125mm
Flicker (FLICKER)
When light and dark alternate over time, the blinking perceived when looking at it
Easier to perceive when this alternation is relatively infrequent
Appears when watching an NTSC TV in a PAL region or a PAL TV in an NTSC region
Field (FIELD)
A screen made up of one vertical scan in TV scanning. In NTSC, the 525 scanning lines consist of an odd field and an even field
Therefore, the field frequency is twice the frame frequency
Resolution (RESOLUTION)
Indicates how finely an imaging system can reproduce the details of a subject; the more pixels, the higher the resolution.
There is horizontal resolution and vertical resolution, but resolution for a CCD camera usually means horizontal resolution. Vertical resolution is determined by the number of scanning lines; in Korea's standard TV system, the number of scanning lines is 525 Lines and the vertical resolution is 350 Lines. In TV, horizontal resolution and vertical resolution sometimes differ. Vertical resolution is fixed by the number of TV scanning lines, so in NTSC, where the number of effective scanning lines is about 480, it is at most about 480 lines. However, because actual TVs use interlaced scanning, only about 70%, around 340 lines, can be seen.
Horizontal resolution is better or worse depending on how much of the high-frequency band of the video signal can be captured. Generally, since TV has an aspect ratio of 3:4, calculating with that coefficient and the video frequency gives about 80 lines per 1 [MHz] of bandwidth. The maximum video signal frequency of TV broadcasting is about 4.2 [MHz], so this gives about 330 lines. However, when a video signal is input to a TV, the horizontal resolution changes with the frequency band of the input. For example, if a signal up to about 6 [MHz] comes in, a horizontal resolution of about 480 lines is obtained. Looking at the frequency bands of actual home VTRs and LDs, LD is about 5 [MHz], Hi8 and S-VHS are also about 5 [MHz], and normal VHS is about 3 [MHz].
Angle of view (ANGLE OF VIEW)
The range of subjects that can be shot within a given frame, expressed as an angle of the optical system.
Generally expressed by the maximum diameter of the frame.
When the frame is rectangular, like a TV screen, it means the range that can be shot along the diagonal. In this case, the horizontal range that can be shot is often used as the horizontal angle of view, and the vertical range as the vertical angle of view.
Pixel (PIXEL)
Means picture element, and refers to the smallest unit dot that makes up the screen.
For example, if a CCD solid-state image sensor has 786 photosensitive pixels horizontally and 494 vertically, it is described as 380,000 pixels in total. As the smallest unit forming an image, an image is formed by an array of colored dots with light and shade. The more pixels, the higher the resolution of the video you can get. Pixels are usually divided into total pixels and effective pixels: all pixels are called total pixels, and effective pixels are the area of all pixels that is actually output as the video signal. Approximate pixel counts: 8mm film (double format) is 50,000; Super 8 or Single 8, the newer formats, have about 1.5 times the area of the old format, so 75,000 pixels; 16mm film is 250,000; 35mm film is 1,160,525 (number of sawtooth waves for horizontal scanning: the standard system of the US, Korea, and Japan); and television is 150,000. The words "hwaso" (Korean for picture element) and "pixel" mean the same thing and are used for all cameras with an image sensor. They are not used for conventional cameras that use photosensitive film.
Luminance (LUMINANCE)
One of the photometric quantities for surface light sources
Luminance signal (LUMINANCE SIGNAL)
An electrical signal representing the luminance of a TV image
White balance (WHITE BALANCE)
A special function used in cameras to maintain original colors; expressed in ˚K and generally ranges between 2,500˚K ～ 7,000 ˚K.
ALC(AUTO LEVEL CONTROL)
To correct the camera's output level to a constant value as the amount of light changes, a servo control system that adjusts the opening and closing of the iris is applied to the camera/
lens system. This system is included in the lens
itself and receives power and video output from the camera.
There is also another system in which the servo system is inside the camera and connects to the lens with 4 wires.
AGC(Automatic Gain Control)
Automatic gain adjustment. When a signal with a strong level over the specification is input, it controls the Gain (meaning the same as film sensitivity) to prevent signal saturation, and for weak signals it raises them to the specified level to keep a constant level.
AWB(AUTO WHITE BALANCE)
A circuit function that automatically adjusts the white balance of a color camera as the color temperature of the light source changes
There is the internal metering method, which uses the voltage obtained by integrating the R/B signals made from the camera signal as color temperature information and FEEDBACK-controls the R/B gains to follow the color temperature locus of the light source, and the external metering method, which detects the color temperature of the light source with an external light sensor and FORWARD-controls the R, G, B gains
BNC
The BNC connector is a connector that connects a coaxial cable to a monitor. Short for Byinet Neil Concelamn, it is used in almost all CCTV and broadcast equipment as the basic
connector for transmitting video signals over coaxial cable.
"C" mount/"CS" mount ("C"MOUNT/"CS"MOUNT)
The typical coupling structure between a CCTV camera and lens
CCTV lenses have 2 types of lens mount: for C-mount lenses the flange back distance is 17526mm, and for CS mount it is 125mm
These days many cameras can use both types of lens mount, and this point is very important for setting up the camera and lens properly
A C-mount lens can be used on a CS-mount camera with a 5mm adapter, but a CS-mount lens cannot be used on a C-mount camera
DC-type auto iris lens (DC TYPE AUTO IRIS LENS)
A type of auto iris lens that has no control circuit in the lens itself; instead, a circuit that keeps the amount of light constant is built externally (in the camera, etc.) so the lens iris can be adjusted automatically
DC IRIS LENS
A type of auto iris lens that has no control circuit in the lens itself; instead, a circuit that keeps the amount of light constant is built externally (in the camera, etc.) so the lens iris can be adjusted automatically.
DSP(DIGITAL SIGNAL PROCESS)
The scope of DSP is unlimited, so limiting the explanation to cameras: digital signal processing means A/D (analog/digital) converting the analog signal (CCD output) and performing algebraic operations on the resulting digital data to carry out signal processing such as filtering or additional functions. Using DSP has the advantage that achieving optimal image quality can be approached easily by manipulating software.
ELC(ELECTRONIC LEVEL CONTROL)
A method that keeps the amount of light constant using the electronic SHUTTER function
The electronic SHUTTER adjusts the amount of charge accumulated in the CCD, so it can adjust the amount of light just like a mechanical iris
That is, operating at a high-speed SHUTTER has the same effect as closing the iris (IRIS),
and operating at a low-speed SHUTTER has the same effect as opening the iris
Using this principle, level control is done by varying the SHUTTER speed according to the amount of light
F-number (F-NUMBER)
A value indicating the brightness of a lens
With the focal length of the optical system as f and the aperture as D, it is written F=f/D
The brightness of the image is inversely proportional to the square of the F-number, so the smaller the F-number, the brighter the optical system
Generally, F-numbers are used on the iris scale marked on lenses,
shown as the numbers 1, 14, 2, 28, 4, 56, 8, 11, 16, a series of √2 in which the brightness halves with each stop
FLANGE BACK
The distance from the lens flange (where the lens mount begins) to the image point.
FLICKERLESS
When the repetition frequency of light and dark is low, the human eye perceives a twinkling, shimmering appearance; this is called flicker, and the brighter the surroundings, the more flicker is perceived even at the same repetition frequency of light and dark. It mainly occurs in environments where the TV system is NTSC (field frequency 60Hz) and the power frequency is 50Hz; to avoid this flicker, the camera's electronic shutter speed is fixed at 1/100 second
and used that way.
FPS
Frame per second (frames per second) or Field per second (fields per second). In image processing,
it is used as a criterion for evaluating performance. High-performance products have a high fps and can also show video in real time.
NTSC(National Television Systems Committee)
The international TV system committee that, together with the FCC, established the US color TV standard, and also that system. The NTSC system was adopted as the color TV standard in the US in 1953 and as the standard in Japan in June 1960. In Korea in 1980, there were opinions from various sectors about NTSC, PAL, and other systems over the introduction of color broadcasting, but the competent authority, the Radio Management Bureau, adopted the NTSC system considering the already allocated channel standards and the characteristics of the broadcast equipment in operation. CCTV systems usually adopt mainly the NTSC system. Most countries use the PAL or NTSC system.
PAL(Phase Alternate Line)
A color encoding/transmission system developed mainly by Bruch of telefunken; PAL is short for Phase Alternate Line. In the PAL encoding system, color information is represented by a subcarrier that depends on the transmitted color and has a specific amplitude and a phase relationship tied to the burst signal. On every second line, the signal phase is inverted by 180° in the demodulation process of the PAL system, and errors in phase or amplitude introduced by the transmission path are averaged and minimized. PAL is used around the world for both UHF and VHF transmission. Most countries generally choose and use one of the two transmission systems, NTSC or PAL.
RCA(RADEO CORPORATION OF AMERICA CABLES)
RCA cables are standard analog cables used to connect audio and video devices to each other. Red is usually for the left audio channel, white for the right audio channel, and yellow for video input. RCA cables are generally thin and perform well at distances of 6M or less. However, at distances over 6M, the unbalanced signal in an RCA cable can be attenuated, and noise and crosstalk can occur.
OSC (On-screen display)
An on-screen display is an image superimposed on the screen picture, commonly used on modern TVs, VCRs, and DVD players to display information such as volume, channel, and time.
Korean: 비균일성 보정 (Non-uniformity correction, NUC)
An operation performed to adjust for small detector drift that occurs as the scene being measured and the environment change; it is sometimes needed when the camera's own heat interferes with temperature measurement.
DIS (Digital Image Stabilization)
When the camera vibrates due to external factors such as wind, it corrects the video automatically and outputs a stable picture. Changing the DIS setting may shrink or enlarge the video picture.

List of CCTV Software

Open Source

Korean CCTV companies

Company

Website

Customer service

ADT Caps

www.adtcaps.co.kr

080 - 786 - 6400

GMT

www.cctvinfo.co.kr

1544 - 1138

KCE

www.kcecctv.co.kr

1644 - 6271

KT Telecop

www.kttelecop.co.kr

1588 - 0112

LG Electronics

www.lgecommercial.com/security-kr

1588 - 7921

NSOK

www.home.nsok.co.kr

1588 - 9112

SK Telecom PointCam

www.tbizpoint.co.kr

1599 - 6409

Nadatel

www.nadatel.com

1588 - 4916

Neocom

www.ncctv.com

032 - 348 - 0842

Duhyun Security

www.duhyun.com

1566 - 7418

Samsung Techwin

www.samsungcctv.co.kr

1588 - 5772

Safe One

www.safe1.co.kr

1577 - 7112

Sysmania

www.sysmania.com

031 -494 - 3501

SeeEyes

www.sscctv.com

070 - 7706 - 3500

CNBTEC (CNB)

www.cnbtec.co.kr

02 - 2109 - 1457

Secuinfo

www.cybersoft.co.kr

031 - 777 - 8470

Ammontec

www.ammon.co.kr

1899 - 0147

IDIS

www.idis.co.kr

1644 - 6440

IseeQ

www.iseeq.co.kr

1800 - 7273

S-1 (S1)

www.s1.co.kr

080 - 023 - 8259

Youngdo Security

www.cctvzone.kr

1599 - 5780

WIN4NET

www.win4net.com

031 - 426 - 5606

EGIPIS

www.egpis.co.kr

1566 - 7503

Rifatron

www.rifatron.com

02 - 3446 - 0053

XyView

www.xysystem.com

02 - 3281 - 9060

KPOL

www.kpol.co.kr

1688 - 0112

Tibet System

www.tibetsystem.com

1899 - 3287

Honeywell

www.honeywell.co.kr/honeywell

02 - 799 - 6208

HIKVISION

www.hikvision.com

1544 - 3193

Hitron

www.hitron.co.kr

02 - 3410 - 9300

Huviron

www.huviron.co.kr

032 - 326 - 8052

RTSP stream URIs and default USER PASSWORD of CCTV manufacturers

Axis Communications
rtsp://root:[email protected]:554/axis-media/media.amp
Hikvision RTSP Stream (NVR)
rtsp://<address>

:<port>/Streaming/Channels/<id>

Samsung / Hanwha Techwin Camera RTSP Stream
rtsp://user:password@<DeviceIP>:port/profile<no>/media.smp

Other IDs to try

  • admin
  • administrator
  • user
  • root

Other passwords to try

  • 0000
  • 1234
  • 12345
  • 12345678
  • 1234567890
  • 1234567890z
  • 1234567890!
  • 1q2w3e4r
  • 1q2w3e4r!
  • 1q2w3e4r5t
  • 1q2w3e4r5t!
  • 1029384756
  • pass

CCTV recording test

  • Recording TS files at 1920x1080, 30 tbr, 90k tbn, 180k tbc, yuv420p(progressive) h264 (High) uses about 23G per 12 hours.
    • Intel i3-8100 @ 3.6GHz (4core)
      • L1d cache 128kiB
      • L1i cache 128kiB
      • L2 cache 1MiB
      • L3 cache 6MiB
      • CPU AVG 30~50 % (with reccd-detectron2)
      • GPU Util 7% (reccd-detectron2)
        • GPU Mem: 4.8G

Documentation

CCTV Installation Failure Cases Guide 2017 (first half)
http://www.tjcctv.co.kr/manual/2017_cctv_installation_guide.pdf
2017_cctv_installation_guide.pdf
Seems to be about Hanwha - Techwin products... Many installation failure cases are compiled in it.

See also

Favorite site

References

  1. Network_Camera_Bandwidth_Effective_Use_Advanced_Guide.pdf ↩

  2. With CBR, the data size is fixed, so it is easy to predict the data size of the whole system. This has the advantage of making the system easy to manage and maintain, but even video with little data is sent at the target bitrate, which can waste network or storage capacity. ↩

  3. VBR is more useful for keeping image quality while using storage capacity and bandwidth efficiently, but when the video suddenly becomes complex, the data size spikes and can put a large momentary load on the network, and because the data size is hard to predict, it is hard to plan storage capacity. ↩

  4. RTSP_Streams_Directions_URLs.pdf ↩

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